Heart stroke volume (SV) determination is used for patient health status monitoring, especially for patients in a CCU (critical care unit) and ICU (intensive care unit). However known clinical methods for measuring and monitoring cardiac output (CO) and SV are typically invasive, involving use of an intra-cardiac catheter and blood pressure based signal acquisition, for example. Known non-invasive and minimally invasive methods for CO/SV estimation, include impedance based methods and the use of angiographic images. But the known methods are usually not accurate or reliable, and need extensive expertise and clinical experience for accurate interpretation and appropriate cardiac rhythm management.
A cardiovascular system comprises components including, a pump (the heart), a carrier fluid (blood), a distribution system (arteries), an exchange system (capillary network), and a collecting system (venous system). Blood pressure is a driving force that propels blood along the distribution network. Stroke volume (SV) is the volume of blood pumped by the right and left ventricle of the heart in one contraction. Specifically, it is the volume of blood ejected from ventricles during systole. The stroke volume does not comprise all of the blood contained in the left ventricle. Normally, only about two-thirds of the blood in the ventricle is ejected with each beat. The blood actually pumped from the left ventricle comprises the stroke volume and it, together with the heart rate, determines the cardiac output (CO). Hemodynamic and cardiac output analysis, such as SV measurement improve analysis and characterization of cardiac pathology and disorders, and even enable prediction of occurrence of life-threatening events. Hence, accurate and precise hemodynamic measurement, parameter calculation, efficient diagnosis, and reliable evaluation are desired to monitor patient health status.
Accurate clinical assessment of circulatory status is particular desirable in critically ill patients in an ICU and patients undergoing cardiac, thoracic, or vascular interventions. As patient hemodynamic status may change rapidly, continuous monitoring of cardiac output provides information enabling rapid adjustment of therapy. CO/SV are important parameters used for cardiac/heart function characterization. Known methods for CO/SV determination include, Fick principle methods, Bio-impedance and conduction methods, Doppler ultrasound, arterial pulse and image contour analysis methods. However these methods have different kinds of limitation and burdens. Known clinical methods for CO/SV calculation are typically invasive, requiring catheters that add to clinical procedure complexity and present risk. Known clinical methods for cardiac output estimation are often complex and time consuming and are unsuited to some clinical environments or for a brief cardiac function check. Known methods for CO/SV estimation, such as indicator dilution techniques, Fick principle, Bio-impedance and conduction methods, use different kinds operating principles resulting in different kinds of data deviation and errors. These cardiac output calculation methods are sensitive to quality of sensor signals and may be unreliable in noisy environments. A system according to invention principles addresses these deficiencies and related problems